High viscosity index lubricants by isoalkane alkylation

ABSTRACT

An isoalkane alkylate base oil and a process to make an isoalkane alkylate base oil having a VI higher than 90, comprising:
         a. selecting an isoalkane feed containing at least one isoalkane and an olefin feed containing at least one linear olefin such that a combined carbon number of the isoalkane feed and the olefin feed is from 20 to 60; and   b. alkylating the isoalkane feed with the olefin feed in the presence of an acidic alkylation catalyst under alkylation conditions to make the isoalkane alkylate base oil having the VI higher than 90;   wherein the isoalkane alkylate base oil has a kinematic viscosity at 100° C. from 2 to 30 mm 2 /s, a pour point less than 0° C., and a bromine index less than 2000 mg Br/100 g.

This application is related to three co-filed applications titled: “BASEOIL HAVING HIGH VISCOSITY INDEX FROM ALKYLATION OF DIMER KETONE-DERIVEDOLEFIN”, “FARNESANE ALKYLATION”, and “ALKYLATION OF METALLOCENE-OLIGOMERWITH ISOALKANE TO MAKE HEAVY BASE OIL”, all herein incorporated in theirentireties.

TECHNICAL FIELD

This application is directed to compositions of an isoalkane alkylatebase oil and a process for alkylating an isoalkane with a linear olefinto produce an essentially aromatics and olefin-free alkylate base oil.The isoalkane alkylate base oil produced can consist predominantly of amixture of isoalkanes in the base oil boiling range. An isoalkanealkylate base oil with a viscosity index in the Group III+ range isattainable.

SUMMARY

This application provides a process to make an isoalkane alkylate baseoil having a VI higher than 90, comprising:

a. selecting an isoalkane feed containing at least one isoalkane and anolefin feed containing at least one linear olefin such that a combinedcarbon number of the isoalkane feed and the olefin feed(N_(alkane+olefin)) is from 20 to 60;

b. alkylating the isoalkane feed with the olefin feed in the presence ofan acidic alkylation catalyst under alkylation conditions to make theisoalkane alkylate base oil having the VI higher than 90, wherein theisoalkane alkylate base oil has a kinematic viscosity at 100° C. from 2to 30 mm²/s, a pour point less than 0° C., and a bromine index less than2000 mg Br/100 g.

This application also provides an isoalkane alkylate base oil that isessentially free of olefins and aromatics and consists predominantly oflong carbon chain molecules having a straight chain of no less than 12carbon atoms and having at least one branch towards the middle of thestraight chain, and characterized by:

a) the isoalkane alkylate base oil contains less than 10 wt % n-alkanes,less than 0.1 wt % olefinic hydrocarbons, and less than 0.1 wt %aromatic hydrocarbons;

b) the at least one branch is a branched alkyl group containing 4 ormore carbon atoms; and

c) the long carbon chain molecules have two terminal linear unbranchedalkyl groups each containing at least 4 carbons.

This application also provides an isoalkane alkylate base oil,characterized by having a total integral of the ¹³C NMR spectrum whereinmore than 25% of the total integral of the ¹³C NMR spectrum falls within¹³C resonances in ranges for linear long chain alkyl groups given by:C1(13.9-14.2 ppm), C2(22.6-22.8 ppm), C3(31.9-32.05 ppm), C4(29.35-29.45ppm), and C5+(29.6-29.8 ppm).

The present invention may suitably comprise, consist of, or consistessentially of, the elements in the claims, as described herein.

GLOSSARY

An “isoalkane” is a hydrocarbon with the general formula C_(n)H_(2n+2),n≧4 characterized by having at least one branch point, which means thatthe molecule contain at least one carbon atom bonded to three othercarbon atoms and one hydrogen atom. The general formula for an isoalkanemay be written as CHRR′R″, wherein R, R′ and R″ are linear or branchedalkyl groups

For example:

“Linear olefins” are unsaturated molecules with a linear hydrocarbonstructure, and without any molecular branches.

“Alpha olefin” refers to any olefin having at least one terminalunconjungated carbon-carbon double bond.

“Base oil” refers to a hydrocarbon fluid to which other oils orsubstances are added to produce a lubricant.

“Lubricant” refers to substances (usually a fluid under operatingconditions) introduced between two moving surfaces so as to reduce thefriction and wear between them.

“Viscosity index” (VI) represents the temperature dependency of alubricant, as determined by ASTM D2270-10(E2011).

“Predominantly” refers to greater than 50 wt %, such as from greaterthan 50 wt % up to 100 wt %, in the context of this disclosure.“Essentially” refers to from 90 wt % to 100 wt % in the context of thisdisclosure.

“API Base Oil Categories” are classifications of base oils that meet thedifferent criteria shown in Table 1:

TABLE 1 API Group Sulfur, wt % Saturates, wt % Viscosity Index I  >0.03and/or <90 80-119 II ≦0.03 and ≧90 80-119 III ≦0.03 and ≧90 ≧120 IV AllPolyalphaolefins (PAOs) V All base oils not included in Groups I - IV(naphthenics, non-PAO synthetics)

“Group II+” is an unofficial, industry-established ‘category’ that is asubset of API Group II base oils that have a VI greater than 110,usually 112 to 119.

“Group III+” is another unofficial, industry-established ‘category’ thatis a subset of API Group III base oils that have a VI greater than 130.

“Catalytic dewaxing”, or “hydroisomerization dewaxing”, refers to aprocess in which normal paraffins are isomerized to their more branchedcounterparts in the presence of hydrogen and over a catalyst.

“Kinematic viscosity” refers to the ratio of the dynamic viscosity tothe density of an oil at the same temperature and pressure, asdetermined by ASTM D445-15.

“LHSV” means liquid hourly space velocity.

“Periodic Table” refers to the version of the IUPAC Periodic Table ofthe Elements dated Jun. 22, 2007, and the numbering scheme for thePeriodic Table Groups is as described in Chemical And Engineering News,63(5), 27 (1985).

“Bromine index” refers to the amount of bromine-reactive material inpetroleum hydrocarbons and is a measure of trace amounts of unsaturatesin these materials. Bromine index is reported in mg Br/100 g of sample.

“Acidic ionic liquid” refers to materials consisting entirely of ions,that can donate a proton or accept an electron pair in reactions, andthat are liquid below 100° C.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a graph of SIMDIS curves of two of the examples in thisdisclosure. One line shows the products of 1-tetradecene (example 1) andthe other line shows the products of isomerized linear tetradecene(example 2).

DETAILED DESCRIPTION

The process comprises selecting an isoalkane feed and an olefin feed.The isoalkane feed contains at least one isoalkane and an olefin feedcontains at least one linear olefin. The combined feeds (isoalkane andolefin) have a combined carbon number (N_(alkane+olefin)) that is from20 to 60. For example, the isoalkane feed can have a feed isoalkanecarbon number (N_(alkane)) greater than 6 and the olefin feed can have alinear olefin carbon number (N_(olefin)) greater than 9, such that thesum of the feed isoalkane carbon number and the linear olefin carbonnumber provides the combined carbon number from 20 to 60. In oneembodiment, the isoalkane feed has a feed isoalkane carbon number(N_(alkane)) of 6 to 50. In one embodiment, the olefin feed has a linearolefin carbon number (N_(olefin)) of 10 to 43.

Isoalkane Feed

In one embodiment, the isoalkane feed is of biological origin. In oneembodiment, the isoalkane feed can be produced by bacteria or yeast fromfatty acids, fatty acid esters, or from free alkanes and alkenes.Examples of biomass that can be used to produce the isoalkane feed areanimal oils and plant oils. In one embodiment, the isoalkane feed can beproduced from animal oils or plant oils by reacting them, or theirby-products, with hydrogen in a hydrodeoxygenation reactor, using ahydrogenation catalyst.

In one embodiment, the isoalkane feed comprise a mixture of isoalkanes.In one sub-embodiment the isoalkane feed comprises a mixture ofisoalkanes that is prepared by oligomerizing C3-C5 olefins to a mixtureof oligomers and subsequently hydrogenating this mixture of oligomers tomake the mixture of isoalkanes. Alkylation of isoalkanes prepared inthis manner with linear alpha olefins has proved to be an effectivemethod for making isoalkane alkylate base oils with very high VIs (i.e.,VI>180) and having good cold flow properties (e.g., lower pour point,lower cold-cranking simulator apparent viscosity, or lower pumpingviscosity by mini-rotary viscometer).

In one embodiment, the isoalkane feed is derived from a C10-C30conjugated hydrocarbon terpene, such as farnesene, myrcene, ocimene,springene, or geranylfarnesene. One example of an isoalkane feed thatcan be derived from a C10-C30 conjugated hydrocarbon terpene isfarnesane.

Farnesane in the shape of 2,6,10 trimethyldodecane has the followingchemical structure:

Hydrogenation of farnesene isomer mixtures produces mixtures oftrimethyldodecane isomers. In the context of this disclosure, the termfarnesane is used to describe both the pure 2,6,10 trimethyl dodecaneprepared from beta farnesene as well as isomer mixtures, including thoseprepared by hydrogenating farnesene isomer mixtures.

Olefin Feed Containing at Least One Linear Olefin

In one embodiment, the at least one linear olefin comprises an internalolefin. For example, the process can comprise isomerizing an alphaolefin to make the internal olefin.

In one embodiment, the at least one linear olefin is an alpha olefin.

In one embodiment, the at least one linear olefin is derived from one ormore ketones. One method to produce the at least one linear olefin fromketones includes the steps of: a) converting an at least one dimericketone to an at least one alcohol, and b) dehydrating the at least onealcohol to make one or more corresponding olefins.

In one embodiment, the olefin feed is of biological origin. In oneembodiment, the olefin feed can be produced by bacteria or yeast fromfatty acids, fatty acid esters, or from free alkanes and alkenes.Examples of biomass that can be used to produce the olefin feed areanimal oils, plant oils, and any carbon source that can be convertedinto one or more terpene compounds. In one embodiment, the olefin feedcan be produced from animal oils or plant oils by partiallyhydrogenating them, or their by-products, with hydrogen in ahydro-deoxygenation reactor or in a hydrogenation reactor, using ahydrogenation catalyst. In one embodiment, the olefin feed comprises anacyclic C10-C30 terpene. In one embodiment, the olefin feed comprises amono olefin derived from pure beta-farnesene. In one embodiment, theolefin feed comprises a mono olefin derived from a mixture of farneseneisomers.

Farnesene is a C15 poly-unsaturated and poly-branched terpene moleculethat may be produced, for example, by fermentation of sugar. In oneembodiment, the farnesene is of biological origin. In one embodiment,the farnesene is produced by a microorganism, including a bio-engineeredmicroorganism. In one embodiment, the farnesene comprises a mixture ofisomers. Farnesene exists in several isomeric forms. The isomer formedby fermentation is typically pure beta-farnesene but mixtures offarnesene isomers may be prepared by other methods from differentstarting materials. For instance, a mixture of farnesene isomers may inprinciple be prepared by trimerisation of isoprene. Farnesene isomermixtures are available from common chemicals supplies. Farnesene ispotentially available in significant volumes at a reasonable price. Byhydrogenating the beta-farnesene, to the corresponding isoalkane,farnesane (2,6,10-trimethyldodecane) can be produced. It is alsopossible by selective hydrogenation to prepare the correspondingmono-olefin (2,6,10-trimethyldodecene). Processes for selectivehydrogenation to produce the mono-olefin farnesene are described in USPatent Pub. No. US20140221258A1.

In one embodiment, the olefin feed is a mixture of linear olefinsobtained by isomerization of an alpha olefin or a mixture of olefinscontaining alpha olefins to increase the content of internal olefins inthe olefin feed. Isomerizing the alpha-olefins in the olefin feed canimprove the cold flow properties of the isoalkane alkylate base oilproduct, as illustrated by comparison of examples 1 and 2 in thisdisclosure.

In one embodiment, the process can additionally comprise passing theolefin feed over an olefin isomerization catalyst to shift a double bondto various different positions without structurally introducingbranching in the at least one linear olefin prior to the alkylating. Thedouble bond shift can improve the possibility to form an isoalkanealkylate base oil with a more diverse composition in the subsequentalkylation step and this favors better cold flow properties.Isomerization of an alpha olefin by double bond shift in the at leastone linear olefin can improve the 1:1 selectivity in the subsequentalkylation, when the acidic alkylation catalyst comprises an acidicionic liquid or HF. A similar phenomenon was observed in ionic liquidcatalyzed isobutane alkylation where 2-butene reacts to formpredominantly the 1:1 alkylate, isooctane, whereas 1-butene gives amixture of 1:1, 2:1, 3:1, and heavier alkylates. When the alpha olefinsshow a marked tendency to form heavier alkylates, the correspondinginternal linear olefins (beta-olefins, gamma-olefins, etc.) can havemuch less tendency to form heavier isoalkane alkylate base oilscomprising more than one olefin unit per unit of isoalkane.

Alkylating

The process to make an isoalkane alkylate base oil comprises alkylatingthe isoalkane feed with the olefin feed in the presence of an acidicalkylation catalyst under alkylation conditions. The alkylating can bedone at an alkylation temperature greater than −20° C., such as from−15° C. to 100° C., or from −10° C. to 50° C.

In one embodiment, the alkylating introduces branching into theisoalkane alkylate base oil at a central position. Introducing thebranching into the alkylate base oil at a central position can increasethe VI and/or reduce the pour point of the isoalkane alkylate base oil.The positioning of the branching in the isoalkane alkylate base oil canbe determined by analyzing a sample of the isoalkane alkylate base oilusing ¹³C NMR (nuclear magnetic resonance).

In one embodiment, the acidic alkylation catalyst is selected from thegroup consisting of an acidic ionic liquid, a sulfuric acid, ahydrofluoric acid, a triflic acid, another Brønsted acid with a Hammetacidity function less than −10 (H₀<−10), an acidic zeolite, a sulfatedzirconia, and a tungstated zirconia. The Hammett acidity function (H₀)is a measure of acidity that is used for very concentrated solutions ofstrong acids, including superacids. It was proposed by the physicalorganic chemist Louis Plack Hammett and is the best-known acidityfunction used to extend the measure of Brønsted—Lowry acidity beyond thedilute aqueous solutions for which the pH scale is useful.

Zeolites useful for alkylating isoalkanes include large pore zeolitessuch as for instance zeolite X and zeolite Y and zeolite beta, in theirproton form or rare earth exchanged form.

In one embodiment, the acidic alkylation catalyst comprises an ionicliquid catalyst and a Brønsted acid. In this embodiment, the Brønstedacid acts as a promoter or co-catalyst. Examples of Brønsted acids aresulfuric acid, HCl, HBr, HF, phosphoric acid, HI, etc. Other strongacids that are proton donors can also be suitable Brønsted acids. In oneembodiment, the Brønsted acid is produced internally within the processby the conversion of an alkyl halide into the corresponding hydrogenhalide. In one embodiment the Brønsted acid is formed by a reaction of aLewis acid component of an ionic liquid, such as chloroaluminate ionsfor instance reacting with a weakly acidic proton donor such as analcohol or water to form HCl.

Acidic Ionic Liquid

Examples of acidic ionic liquid catalysts and their use for alkylationof paraffins with olefins are taught, for example, in U.S. Pat. Nos.7,432,408 and 7,432,409, 7,285,698, and U.S. patent application Ser. No.12/184069, filed Jul. 31, 2008. In one embodiment, the acidic ionicliquid is a composite ionic liquid catalyst, wherein the cations comefrom a hydrohalide of an alkyl-containing amine or pyridine, and theanions are composite coordinate anions coming from two or more metalcompounds.

The most common acidic ionic liquids are those prepared fromorganic-based cations and inorganic or organic anions. The acidic ionicliquid is composed of at least two components which form a complex. Theacidic ionic liquid comprises a first component and a second component.The first component of the acidic ionic liquid will typically comprise aLewis acid compound selected from components such as Lewis acidcompounds of Group 13 metals, including aluminum halides, alkyl aluminumdihalides, gallium halide, and alkyl gallium halide (see the PeriodicTable, which defines the elements that are Group 13 metals). Other Lewisacid compounds besides those of Group 13 metals may also be used. In oneembodiment the first component is aluminum halide or alkyl aluminumdihalide. For example, aluminum trichloride (AlCl₃) may be used as thefirst component for preparing the ionic liquid catalyst. In oneembodiment, the alkyl aluminum dihalides that can be used can have thegeneral formula Al₂X₄R₂, where each X represents a halogen, selected forexample from chlorine and bromine, each R represents a hydrocarbyl groupcomprising 1 to 12 atoms of carbon, aromatic or aliphatic, with abranched or a linear chain. Examples of alkyl aluminum dihalides includedichloromethylaluminum, dibromomethylaluminum, dichloroethylaluminum,dibromoethylaluminum, dichloro n-hexylaluminum,dichloroisobutylaluminum, either used separately or combined.

The second component making up the acidic ionic liquid can be an organicsalt or mixture of salts. These salts may be characterized by thegeneral formula Q+A−, wherein Q+ is an ammonium, phosphonium, boronium,oxonium, iodonium, or sulfonium cation and A− is a negatively chargedion such as Cl⁻, Br⁻, ClO₄ ⁻, NO₃ ⁻, BF₄ ⁻, BCl₄ ⁻, PF₆ ⁻, SbF₆ ⁻, AlCl₄⁻, Al₂Cl₇ ⁻, Al₃Cl₁₀ ⁻, GaCl₄ ⁻, Ga₂Cl₇ ⁻, Ga₃Cl₁₀ ⁻, AsF₆ ⁻, TaF₆ ⁻,CuCl₂ ⁻, FeCl₃ ⁻, AlBr₄ ⁻, Al₂Br₇ ⁻, Al₃Br₁₀ ⁻, SO₃CF₃ ⁻, and3-sulfurtrioxyphenyl.

In one embodiment the second component is selected from those havingquaternary ammonium halides containing one or more alkyl moieties havingfrom about 1 to about 9 carbon atoms, such as, for example,trimethylammonium hydrochloride, methyltributylammonium, 1-butylpyridinium, or alkyl substituted imidazolium halides, such as forexample, 1-ethyl-3-methyl-imidazolium chloride.

In one embodiment, the acidic ionic liquid comprises a monovalent cationselected from the group consisting of a pyridinium ion, an imidazoliumion, a pyridazinium ion, a pyrazolium ion, an imidazolinium ion, aimidazolidinium ion, an ammonium ion, a phosphonium ion, and mixturesthereof. Examples of possible cations (Q+) include abutylethylimidazolium cation [beim], a butylmethylimidazolium cation[bmim], butyldimethylimidazolium cation [bmmim], decaethylimidazoliumcation [dceim], a decamethylimidazolium cation [dcmim], adiethylimidazolium cation [eeim], dimethylimidazolium cation [mmim], anethyl-2,4-dimethylimidazolium cation [e-2,4-mmim], anethyldimethylimidazolium cation [emmim], an ethylimidazolium cation[eim], an ethylmethylimidazolium [emim] cation, anethylpropylimidazolium cation [epim], an ethoxyethylmethylimidazoliumcation [etO-emim], an ethoxydimethylimidazolium cation [etO-mmim], ahexadecylmethylimidazolium cation [hexadmim], a heptylmethylimidazoliumcation [hpmim], a hexaethylimidazolium cation [hxeim], ahexamethylimidazolium cation [hxmim], a hexadimethylimidazolium cation[hxmmim], a methoxyethylmethylimidazolium cation [meO-emim], amethoxypropylmethylimidazolium cation [meO-prmim], a methylimidazoliumcation [mim], dimethylimidazolium cation [mmim], amethylnonylimidazolium cation [mnim], a methylpropylimidazolium cation[mpim], an octadecylmethylimidazolium cation [octadmim], ahydroxylethylmethylimidazolium cation [OH-emim], ahydroxyloctylmethylimidazolium cation [OH-omim], ahydroxylpropylmethylimidazolium cation [OH-prmim], anoctylmethylimidazolium cation [omim], an octyldimethylimidazolium cation[ommim], a phenylethylmethylimidazolium cation [ph-emim], aphenylmethylimidazolium cation [ph-mim], a phenyldimethylimidazoliumcation [ph-mmim], a pentylmethylimidazolium cation [pnmim], apropylmethylimidazolium cation [prmim], a 1-butyl-2-methylpyridiniumcation[1-b-2-mpy], 1-butyl-3-methylpyridinium cation[1-b-3-mpy], abutylmethylpyridinium [bmpy] cation, a1-butyl-4-dimethylacetylpyridinium cation [1-b-4-DMApy], a 1-butyl-4-35methylpyridinium cation[1-b-4-mpy], a 1-ethyl-2-methylpyridiniumcation[1-e-2-mpy], a 1-ethyl-3-methylpyridinium cation[1-e-3-mpy], a1-ethyl-4-dimethylacetylpyridinium cation[1-e-4-DMApy], a1-ethyl-4-methylpyridinium cation[1-e-4-mpy], a 1-hexyl-54dimethylacetylpyridinium cation[1-hx-4-DMApy], a1-hexyl-4-methylpyridinium cation[1-hx-4-mpy], a1-octyl-3-methylpyridinium cation[1-o-3-mpy], a1-octyl-4-methylpyridinium cation[1-o-4-mp y], a1-propyl-3-methylpyridinium cation[1-pr-3-mpy], a1-propyl-4-methylpyridinium cation[1-pr-4-mpy], a butylpyridinium cation[bpy], an ethylpyridinium cation [epy], a heptylpyridinium cation[hppy], a hexylpyridinium cation [hxpy], a hydroxypropylpyridiniumcation [OH-prpy], an octylpyridinium cation [opy], a pentylpyridiniumcation [pnpy], a propylpyridinium cation [prpy], abutylmethylpyrrolidinium cation [bmpyr], a butylpyrrolidinium cation[bpyr], a hexylmethylpyrrolidinium cation [hxmpyr], a hexylpyrrolidiniumcation [hxpyr], an octylmethylpyrrolidinium cation [ompyr], anoctylpyrrolidinium cation [opyr], a propylmethylpyrrolidinium cation[prmpyr], a butylammonium cation [b-N], a tributylammonium cation[bbb-N], a tetrabutylammonium cation [bbbb-N], abutylethyldimethylammonium cation [bemm-N], a butyltrimethylammoniumcation [bmmm-N], a N,N,N-trimethylethanolammonium cation [choline], anethylammonium cation [e-N], a diethylammonium cation [ee-N], atetraethylammonium cation [eeee-N], a tetraheptylammonium cation[hphphphp-N], a tetrahexylammonium cation [hxhxhxhx-N], a methylammoniumcation [m-N], a dimethylammonium cation [mm-N], a tetramethylammoniumcation [mmmm-N], an ammonium cation [N], a butyldimethylethanolammoniumcation [OHe-bmm-N], a dimethylethanolammonium cation [OHe-mm-N], anethanolammonium cation [OHe—N], an ethyldimethylethanolammonium cation[OHe-emm-N], a tetrapentylammonium cation [pnpnpnpn-N], atetrapropylammonium cation [prprprpr-N], a tetrabutylphosphonium cation[bbbb-P], a tributyloctylphosphonium cation [bbbo-P], or combinationsthereof.

In one embodiment, the second component is selected from those havingquaternary phosphonium halides containing one or more alkyl moietieshaving from 1 to 12 carbon atoms, such as, for example,trialkyphosphonium hydrochloride, tetraalkylphosphonium chlorides, andmethyltrialkyphosphonium halide.

In one embodiment, the acidic ionic liquid comprises an unsubstituted orpartly alkylated ammonium ion.

In one embodiment, the acidic ionic liquid is chloroaluminate or abromoaluminate. In one embodiment the acidic ionic liquid is aquaternary ammonium chloroaluminate ionic liquid having the generalformula RR′R″N H+Al₂Cl₇ ⁻, wherein R, R′, and R″ are alkyl groupscontaining 1 to 12 carbons. Examples of quaternary ammoniumchloroaluminate ionic liquids are an N-alkyl-pyridinium chloroaluminate,an N-alkyl-alkylpyridinium chloroaluminate, a pyridinium hydrogenchloroaluminate, an alkyl pyridinium hydrogen chloroaluminate, a dialkyl-imidazolium chloroaluminate, a tetra-alkyl-ammoniumchloroaluminate, a tri-alkyl-ammonium hydrogen chloroaluminate, or amixture thereof.

The presence of the first component should give the acidic ionic liquida Lewis or Franklin acidic character. Generally, the greater the moleratio of the first component to the second component, the greater is theacidity of the acidic ionic liquid.

For example, a typical reaction mixture to prepare n-butyl pyridiniumchloroaluminate ionic liquid is shown below:

In one embodiment, the acidic ionic liquid utilizes a co-catalyst toprovide enhanced or improved alkylation activity. Examples ofco-catalysts include alkyl halide or hydrogen halide. A co-catalyst cancomprise, for example, anhydrous HCl or organic chloride (see, e.g.,U.S. Pat. Nos. 7,495,144 to Elomari, and 7,531,707 to Harris et al.).When organic chloride is used as the co-catalyst with the acidic ionicliquid, HCl may be formed in situ in the apparatus either during thealkylating or during post-processing of the output of the alkylating. Inone embodiment, the alkylating with the acidic ionic liquid is conductedin the presence of a hydrogen halide, e.g., HCl.

The alkyl halides that may be used include alkyl bromides, alkylchlorides and alkyl iodides. Such alkyl halides include but are notlimited to isopentyl halides, isobutyl halides, t-butyl halides, n-butylhalides, propyl halides, and ethyl halides. Alkyl chloride versions ofthese alkyl halides can be preferable when chloroaluminate ionic liquidsare used. Other alkyl chlorides or alkyl halides having from 1 to 8carbon atoms can be also used. The alkyl halides may be used alone or incombination.

When used, the alkyl halide or hydrogen halide co-catalysts are used incatalytic amounts. In one embodiment, the amounts of the alkyl halidesor hydrogen halide should be kept at low concentrations and not exceedthe molar concentration of the AlCl₃ in the acidic ionic liquid. Forexample, the amounts of the alkyl halides or hydrogen halide used mayrange from 0.05 mol %-100 mol % of the Lewis acid AlCl₃ in the acidicionic liquid in order to keep the acidity of the acidic ionic liquidcatalyst at the desired performing capacity.

In one embodiment, the acidic alkylation catalyst comprises an ionicliquid catalyst and a Brønsted acid. In this embodiment, the Brønstedacid acts as a promoter or co-catalyst. Examples of Brønsted acids aresulfuric acid, HCl, HBr, HF, phosphoric acid, HI, etc. Other strongacids that are proton donors can also be suitable Brønsted acids. In oneembodiment, the Brønsted acid is produced internally within the processby the conversion of an alkyl halide into the corresponding hydrogenhalide.

In one embodiment, the process can additionally comprise recycling anexcess of the isoalkane feed to the alkylating. For example, the processcan include distilling out an excess isoalkane after the alkylating andthen recycling the excess isoalkane to the alkylating.

In one embodiment, the process can additionally comprise neutralizing aresidual acidic alkylation catalyst in the isoalkane alkylate base oil.

Isoalkane Alkylate Base Oil

In one embodiment, the isoalkane alkylate base oil has a VI higher than90, a kinematic viscosity at 100° C. from 2 to 30 mm²/s, a pour pointless than 0° C., and a bromine index less than 2000 mg Br/100g. Pourpoint can be determined by ASTM D5950-14, or by an equivalent testmethod.

In one embodiment, the isoalkane alkylate base oil comprises from zeroto less than 5 wt % linear alkanes.

In one embodiment, the isoalkane alkylate base oil comprises from zeroto less than 100 wppm aromatics. In a sub-embodiment, the isoalkanealkylate base oil can comprise from zero to less than 10 ppb aromatics.

In one embodiment, the isoalkane alkylate base oil comprises less fromzero to less than 25 wppm sulfur. In a sub-embodiment, the isoalkanealkylate base oil can comprise from zero to less than 10 ppb sulfur.

In one embodiment the VI is from 91 to 200. In one embodiment the VI ishigher than 120. In different embodiments, the isoalkane alkylate baseoil is an API Group II, an API Group II+, an API Group III, or an APIGroup III+ base oil.

In one embodiment, the isoalkane alkylate base oil comprises a mixtureof isoalkanes, and in a sub-embodiment the isoalkane alkylate base oilcan consist predominantly of a mixture of isoalkanes in the base oilboiling range. The base oil boiling range is defined herein as a boilingpoint range between 550° F. (287.8° C.) and 1292° F. (700° C.), where inthe lower value is the T5 boiling point and the upper value is the T95boiling point. Boiling range is measured by simulated distillationaccording to ASTM D6352-15, or an equivalent test method. An equivalenttest method refers to any analytical method which gives substantiallythe same results as the standard method. T5 relates to the temperatureat which 5 weight percent of the isoalkane base oil has a lower boilingpoint. T95 refers to the temperature at which 95 weight percent of theisoalkane alkylate base oil has a lower boiling point. The isoalkanes inthe base oil boiling range are generally hydrocarbons with 18 to 60carbon atoms.

In one embodiment, the isoalkane alkylate base oil comprises localizedbranching introduced partially from the isoalkane feed and partiallyfrom the alkylating.

The pour point, and other cold flow properties, of the isoalkanealkylate base oil can be excellent. For example, the pour point can beless than or equal to −15° C., less than −24° C., or even less than −50°C.

In one embodiment, the isoalkane alkylate base oil is essentially freeof olefins and aromatics and consists predominantly of long carbon chainmolecules having a straight chain of no less than 12 carbon atoms andhaving at least one branch towards the middle of the straight chain, andcharacterized by:

a) the isoalkane base oil contains less than 10 wt % n-alkanes, lessthan 0.1 wt % olefinic hydrocarbons, and less than 0.1wt % aromatichydrocarbons;

b) the at least one branch is a branched alkyl group containing 4 ormore carbon atoms; and

c) the long carbon chain molecules have two terminal linear unbranchedalkyl groups each containing at least 4 carbons. In a sub-embodiment,the branched alkyl group containing 4 or more carbon atoms can be anisobutyl group, an isohexyl group, a tertiary butyl group, or apoly-branched nonyl group. In a sub-embodiment, the two terminal linearunbranched alkyl groups each containing at least 4 carbons can ben-butyl-, n-pentyl-, or nC_(n)H_(2n+1)—, where n is greater than orequal to 4.

Bromine Index

In one embodiment, the isoalkane alkylate base oil has a bromine indexfrom less than 100 to less than 2000 mg Br/100 g. In one embodiment, theisoalkane alkylate base oil has a bromine index less than 500 mg Br/100g. The bromine index less than 2000 mg Br/100 g, or even less than 200mg Br/100 g can be obtained prior to any subsequent hydrogenation.

Bromine index can be determined by proton Nuclear Magnetic Resonance(NMR). Proton NMR is generally taught inhttps://en.wikipedia.org)wiki/Proton_nuclear_magnetic_resonance.

The following assumptions are made for the Bromine index determinationsin test samples of alkylate base oil:

1) Residual olefins in the test sample are represented by the formula:R1R2C═CHR3, so that one vinylic hydrogen represents an olefin group.

2) The average carbon in the test sample caries two protons and thus maybe represented by an average molecular wt of 14.0268 g/mole

3) All proton resonances in the range 0.5-0.95 represent methyl groups(3 protons per carbon)

4) All proton resonances in the range 0.95-1.40 ppm represent CH₂ groups(2 protons per carbon)

5) All proton resonances in the range 1.4-2.1 ppm represent CH groups (1proton per carbon)

6) All proton resonances in the range 4-6 ppm represent RR′C═CHR″ groups(0.5 proton per carbon or one per double bond).

7) One double bond reacts with one equivalent of bromine, i.e., one moleof olefin reacts with one mole of dibromine (Br₂, MW=159.8 g/mole)

Integrals in the acquired proton NMR spectrum are represented byI(“group”) , e.g., the integral of a methyl group is I(CH3) and theintegral of an olefin group is I(RR′C═CHR″).

Bromine number is defined as the amount of bromine (in g Br₂) needed totitrate all the olefins in 100 g of the test sample. Bromine index=1000*bromine number.

The bromine index is calculated from the proton NMR integrals with thefollowing formula: Bromineindex=1000*100*(159.8/14.0268)*I(RR′C+CHR″)/{0.3333*I(CH3)+0.5*I(CH2)+I(CH)+2*I(RR′C═CHR″)}.

The absence of any proton resonances in the NMR spectrum is interpretedas a bromine index <100, based on the sensitivity of the proton NMRspectrometer that is used.

In one embodiment, the isoalkane alkylate base oil has a bromine indexless than 100.

¹³C NMR

We have discovered that proton decoupled ¹³C NMR offers the opportunityto identify long unbranched terminal alkyl chains and to quantify themrelative to other parts of the molecules and thus allowing to confirmthe structure of an alkylate base oil in which an alkyl group is placedtowards the center of a long straight chain molecule

¹³C NMR is an effective method for identifying the environment of carbonatoms in an organic molecule. In comparison to ¹H NMR the ¹³C NMR coversa far broader range and the ¹³C chemical shift may thus be a more usefultool in the analysis of complex organic materials such as alkylate baseoils.

Hydrocarbon oils such as the materials used for base oil are typicallyvery complex mixtures of predominantly saturated hydrocarbons and the ¹HNMR spectra of these materials are typically not very informative. Incomparison to ¹H NMR, the ¹³C NMR is spread out over s far broaderchemical shift range and ¹³C NMR could thus be more useful tool forcharacterizing base oils, even the proton decoupled ¹³C NMR spectrum istypically complicated. However, we have discovered that surprisinglywhen the base oil is essentially saturated, the ¹³C NMR spectrum can beused to identify the existence of long linear terminal alkyl chains inthe molecules.

In an unbranched chain of carbon atoms ending in a terminal methyl groupof the general formula: CH₃—CH₂—CH₂—CH₂—(CH₂—)_(n)— the ¹³C NMR chemicalshifts of the first 4 carbons (C1-C4 with the terminal methyl being C1)in a long unbranched chain are distinct and well defined and theirexistence in the ¹³C NMR spectrum may therefore be used as probe forlong unbranched terminal carbon chains The subsequent carbons in alinear chain (C5+) all show up in the same narrow resonance range.Labelled from the terminal alkyl the chemical shifts relative to TMS fora long unbranched terminal alkyl chains are as follows:

C1: 13.9-14.2 ppm, C2: 22.6-22.8 ppm, C3 :31.9-32.05 ppm, C4:29.35-29.45 ppm, C5+: 29.6-29.8 ppm.

Since a branch in the carbon chain impacts the chemical shifts of theneighboring 3 carbons the existence of the C1-C5+ series resonances at a1:1:1:1:1 integral intensity is indicative of terminal unbranched 8carbon chains. Additional —CH₂— groups in the chain show up as anincreased integral in the C5+ resonance range. Shorter carbon chains donot exhibit the C5+ resonances but may still show the resonancesanticipated for the first carbon(s) in the long chain range series shownabove. For instance, a linear terminal 5-carbon alkyl group on abranched carbon will exhibit the C1 and C2 resonances in the ranges forlong chain terminal alkyl groups but the C3, C4 and C5 resonances willtypically be shifted out of the long chain resonance ranges given above.

For the application of this method it is important that the integrals ofthe individual resonances represent the relative amounts of the carbonthey represent. Therefore, when acquiring the spectra care is taken toallow sufficient relaxation delay to allow the individual carbons toreturn to their natural state between the pulses. Failure to do thiswould result in some resonances giving smaller integrals than would beanticipated from their abundance. Fortunately, since protons attached toa carbon nucleus helps it relax in the magnetic field this is mostly anissue that carbons not carrying any proton substituents and the carbonresonances used in this method all carry at least 2 hydrogen atoms.

The ¹³C NMR method described above is most useful to identify andquantify the existence of long (C8+) linear alkyl groups in themolecules of hydrocarbon mixtures in the base oil and heavy dieselboiling point ranges.

Provided we have a rough idea of the total carbon number in the averagemolecule in a sample this ¹³C NMR method can be used to evaluate if anoil composed of substantially linear molecules with a few branches hasthese branches in a central part of the main chain or towards the end.If it is towards the end we only expect one long terminal alkyl chainper molecule whereas if the branching is in the center of the chainthere will be two long chain terminal alkyl chains.

Table 2 contains proton decoupled ¹³C NMR spectroscopic data thatillustrates the new method.

TABLE 2 Normalized Integrals Compound C1 C2 C3 C4 C5+ Other n-Octane 1.01.0 1.0 1.0 0.0 0.0 n-Dodecane 1.0 1.0 1.0 1.0 2.1 0.0 n-Hexadecane 1.01.0 1.1 1.0 4.3 0.0 1-Tetradecene 1.0 1.0 1.0 0.9 3.8 5.3 11-Tricosene1.0 1.0 1.1 1.0 3.8 4.2 2,2,4-Trimethylpentane 0.0 0.0 0.0 0.0 0.0 8.0Hydrogenated propylene oligomer 0.0 0.2 0.0 0.0 1.0 64.8 1-C14= +2MePent alkylate 1.0 1.0 0.8 0.8 3.7 2.5 n-C14= isomer mixture + 2MePent1.0 1.3 0.8 1.1 2.2 10.6 alkylate 11-Tricosene + famesane 1.0 1.8 1.01.0 3.5 8.0 11-Tricosene + 2MePent 1.0 1.0 1.1 1.0 3.1 3.011-tricosane + mixed C6, C9 and C12 1.0 1.2 1.0 1.2 4.0 5.6 isoalkanes

In this ¹³C NMR method, C1 refers to 13.9-14.2 ppm, C2 refers to22.6-22.8 ppm, C3 refers to 31.9-32.05 ppm, C4 refers to 29.35-29.45ppm, and C5+ refers to 29.6-29.8 ppm, where C1 represents the terminalmethyl group carbon, C2 represents the methylene group next to theterminal methyl group carbon, and so forth. Where available, theintegrals are normalized relative to the integral of the terminal methylresonance (i.e., C1 around 14.1 ppm) in such a way that the integrals ofother resonances in the spectra are measured relative to this resonance.For the spectra of compounds not containing any long terminal alkylsgroups (e.g., isooctane or hydrogenated propylene oligomer oil) theabsolute values of the integrals are arbitrary.

The three n-alkanes (n-octane, n-dodecane, and n-hexadecane) all exhibitrelative resonances consistent with two terminal alkyl groups of varyinglength. n-Octane is missing the C5+ integrals because the molecule istoo short to have any carbon in a chain that is more than 4 carbons fromthe nearest terminal carbon. Since these three n-alkanes all have twoterminal alkyl groups and thus two terminal methyl groups on long chainalkyl groups. Consequently, normalized integral represents two carbonatoms for each unit in the normalized integrals; n-octane has 0 CS+,n-dodecane has 4 C5+, and n-hexadecane has 8 C5+, so we would expect theC5+ intensities to be 0, 2, and 4 respectively, while the experimentaldata shows 0, 2.1 and 4.3. The deviation reflects the uncertainty in themethod caused by varying relaxation times. While this uncertainty mayimpact the accuracy of an estimate of chain length of very long chainterminal alkyl groups it is insignificant relative to the estimatedabundance of terminal alkyl groups.

For the 1-tetradecene data, the normalized integral represents 1 carbonper unit and again the normalized integrals for C1-C5+ are consistentwith the molecule n-C₁₂H₂₅CH═CH₂ containing 1 terminal long chain alkylgroup. For the 11-tricosene data, the normalized integrals areconsistent with the normalized integrals representing two carbons perunit and are consistent with two long chain terminal alkyl groups in themolecule C₁₁H₂₃CH═CHC₁₀H₂₁.

2,2,4 Trimethylpentane (isooctane) and the hydrogenated propyleneoligomer oil (heavy base oil to bright stock range) are included inTable 2 as examples of two materials that do not contain long chainterminal alkyl groups. The ¹³C NMR spectra of 2,2,4-Trimethylpentane andhydrogenated propylene oligomer consequently do not consistently containresonances in all 5 ranges expected for long chain terminal alkyl groupsand neither contains resonances in the range expected for the 13.9-14.1ppm range where the methyl carbon of a long chain alkyl group would beexpected. It is in particular noteworthy that, while the hydrogenatedpropylene oligomer oil spectrum is quite complicated and (notsurprisingly) some resonances show up within some of the rangesassociated with terminal alkyl groups, more than 98% of the integralarea in the ¹³C NMR of this base oil is outside of these ranges.

The remaining data in Table 2 represent data for various alkylationproducts made by ionic liquid catalyzed alkylation.

Table 2 contains ¹³C NMR data for isoalkane alkylate base oils made byalkylation of 2-methylpentane (isohexane) with 1-tetradecene and with ann-tetradecene isomer mixture respectively. The preparation of these twosamples are further described in Examples 1 and 2, herein. Then-tetradecene isomer mixture may be prepared by isomerization of thealfa olefin (NAO)1-tetradecene through catalytic double bond shift. Itis important to note that the olefin isomerization we used did notintroduce any structural changes in form of branching in the olefin—itonly shifted the double bond from the terminal position to variousinternal positions

The 11-tricosene alkylate data all confirm that the alkylation in thesevery long molecules happens predominantly in the central part of thechain leaving a long straight backbone with two long chain alkyl ends.

The data presented herein show that it is possible to synthesize aunique class of isoalkane alkylate base oils characterized by that thealkylate branching is introduced in the molecule in a central positionsuch that the ¹³C NMR data show intensity in the long chain terminalalkyl group ranges described above corresponding to two long chainterminal alkyl groups per molecule.

In one embodiment, more than 25% of the total ¹³C NMR integrals fallwithin ¹³C NMR resonances in ranges for linear long chain alkyl groupsgiven by: C1(13.9-14.2 ppm), C2(22.6-22.8 ppm), C3(31.9-32.05 ppm),C4(29.35-29.45 ppm), and C5+(29.6-29.8 ppm). In one embodiment, morethan 50% of the total ¹³C NMR integrals fall within ¹³C NMR resonancesin ranges for linear long chain alkyl groups given by: C1(13.9-14.2ppm), C2(22.6-22.8 ppm), C3(31.9-32.05 ppm), C4(29.35-29.45 ppm), andC5+(29.6-29.8 ppm). For example, in one embodiment, the total ¹³C NMRintegrals falling with ¹³C NMR resonances in ranges for linear longchain alkyl groups can be from 26% to 80%.

Finished Lubricant

In one embodiment, the process additionally comprises blending theisoalkane alkylate base oil with at least one additive to make afinished lubricant. A wide variety of high quality finished lubricantscan be made by blending the isoalkane alkylate base oil with at leastone additive selected from the group consisting of antioxidants,detergents, anti-wear agents, metal deactivators, corrosion inhibitors,rust inhibitors, friction modifiers, anti-foaming agents, viscosityindex improvers, demulsifying agents, emulsifying agents, tackifiers,complexing agents, extreme pressure additives, pour point depressants,and combinations thereof; wherein selection of the at least one additiveis directed largely by the end-use of the finished lubricant being made,wherein said finished lubricant can be of a type selected from the groupconsisting of engine oils, greases, heavy duty motor oils, passenger carmotor oils, transmission and torque fluids, natural gas engine oils,marine lubricants, railroad lubricants, aviation lubricants, foodprocessing lubricants, paper and forest products, metalworking fluids,gear lubricants, compressor lubricants, turbine oils, hydraulic oils,heat transfer oils, barrier fluids, and other industrial products. Inone embodiment, the alkylate base oil can be blended with at least oneadditive to make a multi-grade engine oil.

EXAMPLES Example 1 Alkylation of 2-Methylpentane with 1-Tetradecene

400 ml of 2-methyl pentane (isohexane, C₆H₁₄) was combined with 40 mln-butylpyridinium heptachlorodialuminate ionic liquid in a mechanicallystirred 2 liter reaction flask under inert atmosphere and cooled to 3-5°C. on an ice bath. A mixture of 50 ml (37.4 g) 1-tetradecene (C₁₄H₂₈),50 ml 2-methyl pentane and 0.5 ml t-butyl chloride was slowly added overa period of 47 minutes and the agitation was continued for an additional6 minutes before the agitation was stopped and the phases was allowed toseparate. The hydrocarbon phase was decanted off. About 80% of thiscrude hydrocarbon product was cleared by centrifugation and filteredthrough anhydrous MgSO₄. The resulting solution was concentrated on arotary evaporator (RotoVap) to remove volatile components leaving 35 gof an isoalkane alkylate base oil with the properties illustrated inTable 3.

TABLE 3 Viscosity Index 191 Kinematic Viscosity at 100° C., mm²/s 7.705Kinematic Viscosity at 40° C., mm²/s 36.06 Pour Point, ° C. −20 CloudPoint, ° C. −15 Bromine Index, mg Br/100 g estimated <100 from NMR

The proton NMR of the product confirmed that the isoalkane alkylate baseoil was completely saturated and contained no vinylic protons. Theproton NMR confirmed that the isoalkane alkylate base oil was analkylate and not an oligomer. This example demonstrated the process ofthis invention using a combined carbon number of the isoalkane feed andthe olefin feed of 20.

In one embodiment, the kinematic viscosity of the isoalkane alkylatebase oil is higher than would be expected from a C20 isoalkane. This isbecause in alkylation of isoalkanes with alpha olefins the aluminumchloride-based ionic liquid catalysis can result in formation ofproducts incorporating more than one olefin unit and thus forming analkylate product heavier that the simple 1:1 alkylates.

Example 2 Alkylation of 2-Methylpentane with a Mixture of LinearTetradecene Isomers

400 ml of 2-methyl pentane (isohexane) was combined with 40 mln-butylpyridinium heptachlorodialuminate ionic liquid in a mechanicallystirred 2 liter reaction flask under inert atmosphere and cooled to 3-5°C. on an ice bath. A mixture of 50 ml (37.4 g) tetradecene (linearisomer blend prepared from 1-tetradecene by double bond shift) 50 ml2-methyl pentane and 0.5 ml t-butyl chloride was slowly added over aperiod of 34 minutes and the agitation was continued for an additional10 minutes before the agitation was stopped and the phases was allowedto separate. The hydrocarbon phase was decanted off, washed with water,then washed with aqueous sodium bicarbonate, and then filtered throughanhydrous MgSO₄ to produce a clear colorless solution. This solution wasconcentrated on a RotoVap to remove volatile components, leaving 54.3 gof an isoalkane alkylate base oil with the properties shown in Table 4.

TABLE 4 Viscosity Index 123 Kinematic Viscosity at 100° C., mm²/s 2.176Kinematic Viscosity at 40° C., mm²/s 6.921 Pour Point, ° C. −46 CloudPoint, ° C. −36 Bromine Index, mg Br/100 g estimated <100 from NMR

As in Example 1, the proton NMR of the product confirmed that theisoalkane alkylate base oil was completely saturated and contained novinylic protons. The proton NMR confirmed that the isoalkane alkylatebase oil was an alkylate and not an oligomer. This example alsodemonstrated the process of this invention using a combined carbonnumber of the isoalkane feed and the olefin feed of 20. In this examplethe kinematic viscosity of the isoalkane alkylate base oil was shiftedlower (i.e., from 7.705 to 2.176 mm²/s at 100° C.) by using an olefinfeed comprising a linear isomer blend prepared from an alpha olefin bydouble bond shift. The cloud point and pour point were also shifted tolower values. Both of these changes are consistent with an increasedselectivity in the ionic liquid catalyzed alkylation reaction towardsthe 1:1 alkylates.

The effect on the alkylate product of isomerizing the alpha olefin to aninternal olefin is also illustrated in the graphic presentation in FIG.1.

¹³C NMR normalized integrals for the isoalkane alkylate base oilsprepared in Examples 1 and 2 are included in Table 2, provided earlier.The ¹³C NMR data for 1-tetradenene and isomerized n-tetradecenealkylation revealed some surprises. Intuitively, one would expect thatusing internal liner olefins instead of the 1-olefin would give morematerial with two long chain terminal alkyl group by increasing thetendency for introducing the branching of the molecule towards thecenter of the chain but the data show that the effect of the double bondshift in the feed olefin is far more complex.

The data for the 1-tetradecene alkylation show that there is very littleproduct outside the terminal alkyl ranges. Since we know from otherproduct data that the average product molecule made in this alkylationcontained more than one olefin unit per isohexane unit this isconsistent with other data provided that structural isomerization of thelinear C14 chain is limited. However, the intensity of, in particular,the C1 and C2 long chain alkyl resonances compared to the totalintegrals suggest that the molecule contains closer to two terminal longchain alkyl groups than to one suggesting that the i-C6 alkyl group isattached towards the center of the C14 chain.

The data for the alkylate made from isomerized tetradecene show thatmore than 60% of the integrals fall outside the terminal alkyl groupranges and the intensity of the terminal alkyl resonances average toonly about one long chain terminal alkyl group per molecule. Thissuggests that the double bond shift of the olefin aside from improvingthe 1:1 alkane to olefin ratio in the alkylate products has been tocause the alkylation to be accompanied by structural isomerization andintroduction of additional branching in the C14 chain.

In Example 1, 74.5% of the total ¹³C NMR integrals fall within ¹³C NMRresonances in ranges for linear long chain alkyl groups given by:C1(13.9-14.2 ppm), C2(22.6-22.8 ppm), C3(31.9-32.05 ppm), C4(29.35-29.45ppm), and C5+(29.6-29.8 ppm).

In Example 2, 37.6% of the total ¹³C NMR integrals fall within ¹³C NMRresonances in ranges for linear long chain alkyl groups given by:C1(13.9-14.2 ppm), C2(22.6-22.8 ppm), C3(31.9-32.05 ppm), C4(29.35-29.45ppm), and C5+(29.6-29.8 ppm).

Example 3 Ketonization of Lauric Acid (Dodecanoic Acid, Fatty Acid) to12-Tricosanone (Laurone, Ketone) Using an Alumina Catalyst

The ketonization of lauric acid (dodecanoic acid) to 12-tricosanone(laurone, ketone) was catalyzed by an alumina catalyst operated in afixed bed continuously fed reactor at ambient pressure, at a temperaturerange of 770 to 840° C., and with a feed rate that gave a liquid hourlyspace velocity (LHSV) of 0.62 to 0.64 h⁻¹. The conversion of lauric acidto laurone was calculated based on the composition of the product, asdetermined by gas chromatography (GC) using a flame ionization detector(FID).

The freshly loaded new alumina catalyst was calcined in the reactor at482° C. (900° F.) with a stream of dry nitrogen (2 volumes of nitrogenper volume of catalyst per minute) for 2 hours. Then the temperature waslowered to 410° C. (770° F.), the nitrogen stream was stopped, and thelauric acid feed was introduced into the reactor. Product compositionanalysis showed that the fresh catalyst operating at 410° C., LHSV=0.62to 0.64 h⁻¹, gave a lauric acid conversion of 62 to 66 wt %.

The reactor effluent was split in a continuously operated strippingcolumn from which the laurone product was isolated as a bottom cutcontaining less than 1 wt % unconverted lauric acid. The unconvertedfatty acid (lauric acid) taken overhead from the stripping column wasrecycled to the reactor, except for a small amount (<5 wt % relative tothe fresh fatty acid feed stock) of light cracked products. The lightcracked products were predominantly n-alkanes and linear alpha olefins.The light cracked products were withdrawn from the stripping column asthe only by-product stream.

Example 4 Hydrogenation of 12-Tricosanone to 12-Tricosanol overRuthenium/Carbon Catalyst

12-tricosanone (laurone, ketone) prepared as described in Example 3 washydrogenated over a carbon supported ruthenium catalyst to make thecorresponding alcohol, 12-tricosanol as described here.

800 g of the 12-tricosanone was loaded into a 1 liter stirred batchautoclave together with 1 g of a catalyst having 5 wt % ruthenium oncarbon. The mixture of the 12-tricosanone and catalyst was put under1500 psig (10342 kPa) hydrogen pressure, stirred, and heated to 200° C.Hydrogen was added as it was consumed in order to maintain the hydrogenpressure in the reactor during the run. After 23 hours the reaction wasstopped and the reactor contents withdrawn and filtered to yield the12-tricosanol product. Proton nuclear magnetic resonance (NMR) indicatedthat the conversion was about 89 wt % and the selectivity to the alcoholwas greater than 90 wt %, with the corresponding alkane, tricosane,being the only by-product.

Example 5 Hydrogenation of 12-Tricosanone to 12-Tricosanol OverRuthenium/Tin/Carbon Catalyst

2185 g of 12-tricosanone prepared as described in Example 3 was loadedinto a 1 gallon (3.785 liters) stirred autoclave with 3 g of a catalystcomprising 5 wt % ruthenium on a tin promoted carbon support. Themixture of the 12-tricosanone and catalyst was put under 1500 psig(10342 kPa) hydrogen pressure, stirred, and heated to 200° C. Hydrogenwas added as it was consumed in order to maintain the hydrogen pressurein the reactor during the run. After 36 hours the reaction was stoppedand the reactor contents withdrawn and filtered to yield the12-tricosanol product. Proton nuclear magnetic resonance (NMR) indicatedthat the conversion was about 93 wt % and the selectivity to12-tricosanol was about 95 wt %. Later analysis of the olefin isolatedby dehydration of the 12-tricosanol product (see Example 7) showed thatthe product contained less than 2 wt % alkane, indicating greater than98 wt % selectivity in this hydrogenation step.

Example 6 Dehydration of 12-Tricosanol to a Mixture of PredominantlyCis, Trans-11-Tricosene Over an Alumina Catalyst

The 12-tricosanol, made as described in Example 5, was used as preparedwithout further purification. The 12-tricosanol was fed at a LHSV of0.4-0.53 hr⁻¹ to a fixed bed reactor containing 50 ml freshlyregenerated alumina catalyst of the same kind used for the ketonizationdescribed in Example 1. The regeneration of the alumina catalyst wasdone by contacting the catalyst with an oxidizing gas to remove coke andfurther contacting the catalyst with steam, as described in a U.S.patent application Ser. No. 14/540723, filed Nov. 13, 2014.

GC and NMR analysis of the product withdrawn from the fixed bed reactor,after ejection of water, showed a 12-tricosanol conversion of 87 to 90wt %, and near quantitative (about 99 wt %) selectivity to a mixture ofcis and trans 11-tricosene, with only traces of other olefin isomers.The GC and NMR analysis showed the presence of 2 wt % tricosane relativeto the combined tricosane and tricosene carried over from thehydrogenation step described in Example 5.

Example 7 Hydrogenation of 12-tricosanone to 12-Tricosanol overPt/Carbon Hydrogenation Catalyst

12-tricosanone (laurone, ketone) prepared as described in Example 3 washydrogenated over a carbon supported platinum catalyst to make thecorresponding alcohol, 12-tricosanol as described here.

The 12-tricosanone was introduced as a liquid flow (4.1-4.4 g/hr, 12-13mmoles/hr) together with hydrogen (100 Nml/min, 250 mmoles/hr) to afixed reactor holding 7 ml of a catalyst comprising 0.5 wt % platinum oncarbon. The amount of the catalyst was 3.5 g, and the catalyst had aparticle size of 0.3 to 1 mm. The pressure was held at 1500 psig (10342kPa). The liquid products were collected after the reaction and analyzedby GC. The liquid product stream contained three components: 1)unconverted 12-tricosanone, 2) 12-tricosanol, and 3) the correspondingn-alkane, n-tricosane. The n-tricosane was present only in traceamounts.

At a reaction temperature from 450 to 470° F. (232.2 to 243.3° C.), theGC analysis of the product showed a conversion of 12-tricosanone of 80to 87 wt %, and a selectivity to 12-tricosanol of 98.9 to 99.4 wt %. Theremaining 0.6 to 1.1 wt % of the product was n-tricosane formed byhydro-deoxygenation of the alcohol.

Example 8 Isolation of Tricosene from Crude Tricosene Product

Several efficient methods can be used for separation of tricosene fromunconverted 12-tricosanol and 12-tricosanone. One method exploited thefar higher solubility of the olefin in light alkane solvents at lowtemperature. It was possible to perform the separation of the tricoseneby dissolving the mixture of tricosene, tricosanol, and tricosanone inhexane and cooling the dissolved mixture to −20° C. to precipitate outessentially all of the unconverted tricosanol and tricocanone. The solidprecipitates were removed by filtration and after subsequent evaporationof the hexane solvent, a purified tricosene product containing 0.02 wt %tricosanol and 0.9 wt % tricosanone was isolated.

Another method used for separating the tricosene removed the tricosanoland tricosanone from the tricosane by passing a solution of the crudemixture in a hydrocarbon solution through a column of dry silica gelsorbent. The dry silica gel sorbent selectively adsorbed the tricosanoland tricosanone, and left the tricosene in the eluent from the columnwith essentially no tricosanol and only traces of tricosanone.

Although this example speaks of our experiments with tricosene, theseparation methods described in this example can also be used to isolateother olefins prepared in similar manners from other fatty acid derivedketones.

Example 9 Alkylation of Farnesane with Tricosene Using an Ionic LiquidCatalyst

Farnesane (trimethyldodecane, a C15 isoalkane) was prepared byhydrogenation of farnesene (mixture of isomers, acquired from SigmaAldrich) over a fixed bed of 20.7 wt % nickel on alumina catalyst(Johnson Matthey HTC500) at 320° F. (160° C.) and about 1700 psig (11721kPa) using an LHSV of about 0.6-0.8 hr⁻¹.

400 ml of the prepared farnesane was combined with 40 mln-butylpyridinium heptachlorodialuminate ionic liquid catalyst in amechanically-stirred 2 liter reaction flask under inert atmosphere(nitrogen) and cooled to 4° C. on an ice bath. A mixture of 50 ml (39.6g) 11-tricosene (C23 olefin, prepared as described in other examples)and 0.5 ml t-butyl chloride was added to the reaction flask over aperiod of 50 minutes, while the reaction temperature was maintained at3-5° C. After an additional 10 minutes the stirring was stopped, theionic liquid phase was allowed to settle out, and the hydrocarbon phasewas decanted off. The hydrocarbon phase was stirred with ice and enoughsodium bicarbonate (NaHCO₃) to neutralize the residual ionic liquidcatalyst. Subsequently, the excess farnesane was distilled out at up to149° C. and 2 torr on a RotoVap at 8 torr and 91° C., to isolate ayellow viscous oil. The isolated yellow viscous oil had the followingproperties, as shown in Table 5.

TABLE 5 Viscosity Index 129 Kinematic Viscosity at 100° C., mm²/s 11.16Kinematic Viscosity at 40° C., mm²/s 79.93 Pour Point, ° C. −25 BromineIndex, mg Br/100 g estimated 500 from NMR

A proton NMR of the yellow viscous oil confirmed that it was saturatedand contained no vinylic protons. This confirmed that the yellow viscousoil was an alkylate, and not an oligomer.

¹³C NMR normalized integrals of this isoalkane alkylate base oil areshown in Table 2 of this disclosure. In Example 9, 50.9% of the total¹³C NMR integrals fall within ¹³C NMR resonances in ranges for linearlong chain alkyl groups given by: C1(13.9-14.2 ppm), C2(22.6-22.8 ppm),C3(31.9-32.05 ppm), C4(29.35-29.45 ppm), and C5+(29.6-29.8 ppm).

Example 10 Alkylation of Farnesane with 1-Dodecene Using an Ionic LiquidCatalyst

400 ml of farnesane, prepared from farnesene as described in Example 9,was combined with 40 ml n-butylpyridinium heptachlorodialuminate ionicliquid catalyst and 0.1 ml t-butyl chloride in a mechanically-stirred 2liter reaction flask under inert atmosphere (nitrogen) and cooled to 3°C. on an ice bath.

A mixture of 50 ml (37.4 g) 1-dodecene (C12) and 0.5 ml t-butyl chloridewas added to the reaction flask over a period of 34 minutes, while thereaction temperature was maintained at about 3° C. The agitation wascontinued for an additional 10 minutes, then stirring was stopped, theionic liquid phase was allowed to settle out, and the hydrocarbon phasewas decanted off. The hydrocarbon phase was stirred overnight with waterand enough sodium bicarbonate (NaHCO₃) to neutralize the residual ionicliquid catalyst. Subsequently, the hydrocarbon phase was concentrated ona RotoVap at 2 ton and 144° C., which removed the excess farnesane andisolated 75.8 g of a yellow oil.

The yellow oil product that was isolated was an isoalkane alkylate baseoil having the properties as shown in Table 6.

TABLE 6 Viscosity Index 122 Kinematic Viscosity at 100° C., mm²/s 9.854Kinematic Viscosity at 40° C., mm²/s 70.35 Cloud Point, ° C. <−60 PourPoint, ° C. −52 Bromine Index, mg Br/100 g est. from <100 NMR

A proton NMR of this yellow oil product confirmed that it was completelysaturated and contained no vinylic protons. The proton NMR confirmedthat this yellow oil product was an alkylate, and not an oligomer.

Example 11 Alkylation of C6-C12 Isoalkanes with Tricosene (C23) Using anIonic Liquid Catalyst

A sample of C6-C12 isoalkanes was isolated as the naphtha cut of asaturated propylene oligomer product made by hydrogenating lightpropylene oligomers made by metallocene catalyzed oligomerization ofpropylene. The sample of C6-C12 isoalkanes comprised methyl pentane,dimethyl heptane, and trimethyl nonane. Gas chromatographic analysis ofthe sample of C6-C12 isoalkanes revealed the following composition: 38wt % 2-methylpentane, 52 wt % dimethylheptane, 8 wt % trimethylnonane,and 2 wt % heavier isoalkanes.

600 ml (384 g) of the sample of the above mentioned C6-C12 isoalkanemixture was combined with 40 ml n-butylpyridinium heptachlorodialuminateionic liquid catalyst in a mechanically-stirred 2 liter reaction flaskunder inert atmosphere (nitrogen) and cooled to 2° C. on an ice bath. Amixture of 60 ml (47.6 g) tricosene and 0.6 ml t-butyl chloride wasadded to the reaction flask over a period of about 1 hour, while thereaction temperature was maintained at about 2° C. The stirring wasstopped, the ionic liquid phase was allowed to settle out, and thehydrocarbon phase was decanted off. The hydrocarbon phase was treatedwith water and enough sodium bicarbonate (NaHCO₃) to neutralize theresidual ionic liquid catalyst. Subsequently, the excess C6-C12isoalkanes were distilled out as the hydrocarbon phase, and wereconcentrated on a RotoVap at 9 torr and 92° C., to isolate a yellowishisoalkane alkylate base oil.

A SIMDIS analysis of the isolated yellowish isoalkane alkylate base oilrevealed that the isolated oil still contained significant amounts ofmaterial with a boiling point less than 200° C. The isolated yellowishisoalkane alkylate base oil was then heated to 125° C. in a stream ofnitrogen for about 1 hour to remove residual light hydrocarbons andproduce a final product. The final product was an isoalkane alkylatebase oil having the properties as shown in Table 7.

TABLE 7 Viscosity Index 182 Kinematic Viscosity at 100° C., mm²/s 5.047Kinematic Viscosity at 40° C., mm²/s 20.94 Pour Point, ° C. −26 VI/KV10036.06 Bromine Index, mg Br/100 g 1800

¹³C NMR normalized integrals of this isoalkane alkylate base oil arealso shown in Table 2 of this disclosure. In Example 11, 52.5% of thetotal ¹³C NMR integrals fall within ¹³C NMR resonances in ranges forlinear long chain alkyl groups given by: C1(13.9-14.2 ppm), C2(22.6-22.8ppm), C3(31.9-32.05 ppm), C4(29.35-29.45 ppm), and C5+(29.6-29.8 ppm).

It is notable that in all of the examples described above, nohydroisomerization dewaxing was used to make the isoalkane alkylate baseoils. All of these examples of the isoalkane alkylate base oils werealso made without any subsequent hydrogenation after the alkylating, yetstill had low bromine indexes.

The transitional term “comprising”, which is synonymous with“including,” “containing,” or “characterized by,” is inclusive oropen-ended and does not exclude additional, unrecited elements or methodsteps. The transitional phrase “consisting of” excludes any element,step, or ingredient not specified in the claim. The transitional phrase“consisting essentially of” limits the scope of a claim to the specifiedmaterials or steps “and those that do not materially affect the basicand novel characteristic(s)” of the claimed invention.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Furthermore, all ranges disclosed herein are inclusive ofthe endpoints and are independently combinable. Whenever a numericalrange with a lower limit and an upper limit are disclosed, any numberfalling within the range is also specifically disclosed. Unlessotherwise specified, all percentages are in weight percent.

Any term, abbreviation or shorthand not defined is understood to havethe ordinary meaning used by a person skilled in the art at the time theapplication is filed. The singular forms “a,” “an,” and “the,” includeplural references unless expressly and unequivocally limited to oneinstance.

All of the publications, patents and patent applications cited in thisapplication are herein incorporated by reference in their entirety tothe same extent as if the disclosure of each individual publication,patent application or patent was specifically and individually indicatedto be incorporated by reference in its entirety.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. Many modifications of the exemplaryembodiments of the invention disclosed above will readily occur to thoseskilled in the art. Accordingly, the invention is to be construed asincluding all structure and methods that fall within the scope of theappended claims. Unless otherwise specified, the recitation of a genusof elements, materials or other components, from which an individualcomponent or mixture of components can be selected, is intended toinclude all possible sub-generic combinations of the listed componentsand mixtures thereof.

The invention illustratively disclosed herein suitably may be practicedin the absence of any element which is not specifically disclosedherein.

1. A process to make an isoalkane alkylate base oil having a VI higherthan 90, comprising: a. selecting an isoalkane feed containing at leastone isoalkane and an olefin feed containing at least one linear olefinsuch that a combined carbon number of the isoalkane feed and the olefinfeed (N_(alkane+olefin)) is from 20 to 60; and b. alkylating theisoalkane feed with the olefin feed in the presence of an acidicalkylation catalyst under alkylation conditions to make the isoalkanealkylate base oil having the VI higher than 90; wherein the isoalkanealkylate base oil has a kinematic viscosity at 100° C. from 2 to 30mm²/s, a pour point less than 0° C., and a bromine index less than 2000mg Br/100 g.
 2. The process of claim 1, wherein the isoalkane feed has afeed isoalkane carbon number (N_(alkane)) of 6 to 50 and the olefin feedhas a linear olefin carbon number (N_(olefin)) of 10 to
 43. 3. Theprocess of claim 1, wherein the at least one linear olefin comprises aninternal olefin.
 4. The process of claim 3, additionally comprisingisomerizing an alpha olefin to make the internal olefin.
 5. The processof claim 1, wherein the at least one linear olefin is an alpha olefin.6. The process of claim 1, wherein the olefin feed is of biologicalorigin.
 7. The process of claim 1, wherein the acidic alkylationcatalyst is selected from the group consisting of an acidic ionicliquid, a sulfuric acid, a hydrofluoric acid, a triflic acid, anotherBrønsted acid with a Hammet acidity function less than −10 (H₀<−10), anacidic zeolite, a sulfated zirconia, and a tungstated zirconia.
 8. Theprocess of claim 1, wherein the acidic alkylation catalyst comprises anionic liquid and a Brønsted acid.
 9. The process of claim 8, wherein theionic liquid is a chloroaluminate and the Brønsted acid is hydrogenchloride.
 10. The process of claim 1, wherein the alkylating introducesbranching into the isoalkane alkylate base oil at a central position.11. The process of claim 1, additionally comprising recycling an excessof the isoalkane feed to the alkylating.
 12. The process of claim 1,wherein no hydroisomerization dewaxing is used.
 13. The process of claim1, wherein the isoalkane alkylate base oil comprises from zero to lessthan 5 wt % linear alkanes.
 14. The process of claim 1, wherein theisoalkane alkylate base oil comprises from zero to less than 100 wppmaromatics.
 15. The process of claim 1, wherein the isoalkane alkylatebase oil is an API Group III+ base oil.
 16. The process of claim 1,wherein the isoalkane alkylate base oil comprises a mixture ofisoalkanes.
 17. The process of claim 1, wherein the isoalkane alkylatebase oil comprises localized branching introduced partially from theisoalkane feed and partially from the alkylating.
 18. The process ofclaim 1, wherein the pour point is less than or equal to −15° C.
 19. Theprocess of claim 1 wherein the VI is higher than
 120. 20. The process ofclaim 1 wherein the bromine index is less than 500 mg Br/100 g.
 21. Theprocess of claim 1, additionally comprising blending the isoalkanealkylate base oil with at least one additive to make a finishedlubricant.
 22. An isoalkane alkylate base oil, made by the process ofclaim
 1. 23. An isoalkane alkylate base oil that is essentially free ofolefins and aromatics and consists predominantly of long carbon chainmolecules having a straight chain of no less than 12 carbon atoms andhaving at least one branch towards the middle of the straight chain, andcharacterized by: a) the isoalkane alkylate base oil contains less than10 wt % n-alkanes, less than 0.1 wt % olefinic hydrocarbons, and lessthan 0.1wt % aromatic hydrocarbons; b) the at least one branch is abranched alkyl group containing 4 or more carbon atoms; and c) the longcarbon chain molecules have two terminal linear unbranched alkyl groupseach containing at least 4 carbons.
 24. An isoalkane alkylate base oil,characterized by having a total integral of the ¹³C NMR spectrum whereinmore than 25% of the total integral of the ¹³C NMR spectrum falls within¹³C NMR resonances in ranges for linear long chain alkyl groups givenby: C1(13.9-14.2 ppm), C2(22.6-22.8 ppm), C3(31.9-32.05 ppm),C4(29.35-29.45 ppm), and C5+(29.6-29.8 ppm).
 25. The isoalkane alkylatebase oil according to claim 24, wherein more than 50% of the totalintegral of the ¹³C NMR spectrum falls within the ¹³C resonances in theranges for linear long chain alkyl groups.